New Mexico Butterfly Joins ESA List Despite Rancher Concerns

by Michael Doyle, Greenwire

The Fish & Wildlife Service (FWS) has listed the Sacramento Mountains checkerspot butterfly as an endangered species, reversing earlier assessments against the wishes of some ranchers in New Mexico.

Citing in part drought driven by climate change, the federal agency concluded the small butterfly requires Endangered Species Act protections that had been denied in 2004 and again in 2009. One contributing factor is the loss of host plants and nectar sources during the summer.

“Despite large precipitation events during the summer months of 2021, the Sacramento Mountains remain in a moderate to severe drought, and impacts to the butterfly’s habitat from climate change are likely to continue,” the FWS stated.

Grazing, recreation, the spread of invasive and nonnative plants, and changing wildfire conditions have also undermined the butterfly’s habitat, according to the agency.

The butterfly currently inhabits Bailey Canyon and Pines Meadow Campground in the Sacramento Mountains. During the 2020 survey season, eight butterflies were detected in both meadows combined. In 2021, surveys detected 23 adult butterflies.

“In addition, the overall meadow condition for these sites was low because there are few host plants and nectar sources present,” the FWS reported.

The decision to list the species under the ESA comes about one year after the idea was proposed. Although the proposal did not excite widespread controversy, it did alarm some who fear they may be directly affected (Greenwire, January 24, 2022).

“We believe that the FWS may not have followed lawful procedures, that some information provided is misleading, and that there are too many unknown variables to warrant the listing of the [butterfly] as endangered,” wrote Gary Scarbrough, chairman of the Public Land Use Advisory Council, for Otero County, New Mexico.

The FWS is not yet proposing to designate critical habitat for the species.

The butterfly is a subspecies of the Anicia checkerspot, living in the Sacramento Mountains in south-central New Mexico. It has a wingspan of approximately two inches and a checkered pattern with dark brown, red, orange, cream and black spots.

It relies on a perennial plant called the New Mexico beardtongue and, for nectar, on a plant called the orange sneezeweed.

FWS explained that problems for the plants, and hence for the butterflies, arose when feral horses were inadvertently released onto the Lincoln National Forest around 2012. Roughly 60,000 horses now live throughout the Sacramento Mountains.

New Mexico beardtongue is usually not a main food source for horses. But as drought has dried up other food plants, the horses switched diets and start going after the plants that the butterfly needs.

An organization that was then called the Southwest Center for Biological Diversity filed a petition in 1999 requesting emergency listing of the Sacramento Mountains checkerspot butterfly as endangered.

In 2001, FWS proposed listing the species, but a few years later reversed its position, stating that “the threats to the species were not as great as we had perceived when we proposed it for listing.”

In 2007, the Center for Biological Diversity and the group now called WildEarth Guardians filed another petition, citing threats including horse grazing, climate change and an imminent plan to spray for insect pests.

In September 2009, FWS again determined listing was not warranted.

“Since we published the not-warranted rule in 2009, drought from climate change has worsened in New Mexico, worsening habitat conditions for the Sacramento Mountains checkerspot butterfly,” the FWS explained last year. “Further, during abnormally dry conditions, both feral horses and elk switch to browsing certain plants that are important for the butterfly. Additionally, recreation on the Lincoln National Forest has increased in recent years.”

The agency initiated a review of the species in January 2021. That March, the Center for Biological Diversity filed another petition to list the butterfly as endangered with critical habitat. The FWS said it included the information provided in the petition in the analysis of the species’ status. ▫